Not Applicable
1. Field of the Invention
This invention relates to self supercharging internal combustion engines and particularly to crankcase inducted self-supercharging four-cycle internal combustion engine.
2. Description of Related Art
Several patents have been issued relating to the use of the crankcase as an air chamber to enhance combustion air in an engine. These patents cover both two stroke and four stroke engines. For example, U.S. Pat. No. 3,973,532 to Litz uses a sealed crankcase to draw air into the engine. This air is then compressed and stored in a holding tank, where it is drawn into the cylinder on the intake stroke. This compressed air supercharges the fuel mixture before the normal compression stroke. One problem with this design is that it requires a separate sir tank to be added to the engine. Another problem is that it only draws a single charge of air over two of the cycles. While this does provide additional air, it does so inefficiently.
U.S. Pat. No. 5,377,634 to Taue teaches another engine that uses the crankcase as a compression chamber for air. Again, the problem is that the chamber is small and the amount of air being compressed and pumped is limited by what one cylinder can pump and compress. U.S. Pat. Nos. 5,230,314, 5,657,724, 4,282,845, and 4,545,346 all teach use of a crankcase as a compression chamber to compress air for combustion. They all suffer from the same volume limitations that limit the amount of air that can be compressed to that produced by one cylinder.
U.S. Pat. No. 5,105,775 takes the use of the crankcase combustion chamber in a slightly different direction. Here, the crankcase is divided into a number of sealed chambers. Adjacent chambers are interconnected. Because of the timing differences between the cylinders, this allows one cylinder to charge the other cylinder and vice versa. This then eliminates the need for a separate holding tank, because each cylinder""s crankcase acts as the holding tank for the other. Despite the reduction in equipment needed, the fundamental limitation remains in that the air being compressed remains that volume that can be handled by one cylinder.
The instant invention is a crankcase inducted self-supercharging four-cycle internal combustion engine that uses cylinder pairs to as an induction pump. The cylinder pairs are arranged in a 360-degree crank throw so that both pistons rise and fall together. The cylinders are synchronized so that when one cylinder is on the intake stroke, the other is on the power stroke. When one cylinder is on the exhaust stroke, the other is on the compression stroke.
A two-cycle reed valve is installed on a crankcase inlet port to draw air into the crankcase on the upstroke of the pistons. Since both pistons rise and fall together, each upstroke draws a volume of air equal to the volume of two pistons into the crankcase. When both pistons are on the down stroke, this double volume of air is then moved into a manifold connecting the crankcase to the inlet valves of the cylinders. This air is then pumped into each cylinder alternately on each intake stroke. In this way, it is possible to increase the air available for each cylinder by a factor of two without having to resort to storage tanks or other devices. Moreover, there is no wasted movement in compressing the air because each intake stroke draws in twice the volume of one cylinder. The double volume of air is then delivered into one cylinder, which automatically compresses the air in the cylinder without having to store it or compress it separately.